In my own headcannon,mage inquisitor used up most of her magic during the last fight and to keep from getting frostbite on the trip over the mountains. After all you could have drained your mana. The non-mages most likely lost a couple toes to the cold.

@Rivka: Well, yeah I think that's one of the best headcannons for this. But the system in place does allow you for mana regeneration pretty quickly regardless of being in battle or not. I feel like this is a phoenix down sorta situation where gameplay mechanics and cinematics just don't overlap at all.

@ScreamingViking: Oh I can imagine! You know, of all the mobs in inquisition the despair demons were always the worst for me...

It's especially odd for Qunari (er, Vashoth... however you want to call them) mages, because in the first game they were vulnerable to cold in-game, the story reason being they're so adapted for hot environments. You'd think a Vashoth mage would learn a few tricks for when they were assigned somewhere with snow.